/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.api.connector.sink2;

import org.apache.flink.annotation.Public;

import java.io.IOException;
import java.util.Collection;

/** A {@link SinkWriter} that performs the first part of a two-phase commit protocol. */
@Public
public interface CommittingSinkWriter<InputT, CommittableT> extends SinkWriter<InputT> {
    /**
     * Prepares for a commit.
     *
     * <p>This method will be called after {@link #flush(boolean)} and before {@link
     * StatefulSinkWriter#snapshotState(long)}.
     *
     * @return The data to commit as the second step of the two-phase commit protocol.
     * @throws IOException if fail to prepare for a commit.
     */
    Collection<CommittableT> prepareCommit() throws IOException, InterruptedException;
}
